Antenna unit and array applied to low-orbit satellite internet broadband common-aperture terminal

Abstract

The application relates to the technical field of satellite communication antennas, and discloses an antenna unit applied to a low-orbit satellite internet broadband common-aperture terminal and an array, which comprises, from bottom to top, a substrate layer, a middle layer and a top layer which are fixedly connected in sequence; wherein the upper surface of the top layer is etched with an outer ring metal cap, and the upper surface of the top layer is also pasted with a transmitting patch and a receiving patch which are both subjected to corner cutting treatment; a U-shaped gap with equal arm lengths is arranged in the transmitting patch, and a first feeding coaxial is arranged vertically to the surface of the transmitting patch; the middle layer is provided with a T-shaped metal patch; a second feeding coaxial is arranged vertically to the surface of the transmitting patch, and the top and bottom of the second feeding coaxial are connected with the receiving patch and the T-shaped metal patch respectively. The application solves the strong coupling problem between the transmitting and receiving units of a traditional common-aperture antenna through a center short circuit structure and a different layer feeding method.

Description

Technical Field

[0001] This invention relates to the field of satellite communication antenna technology, specifically to an antenna element and array for use in a low-orbit satellite internet broadband common-aperture terminal. Background Technology

[0002] A common-aperture antenna refers to an antenna that places multiple antennas of different frequency bands within the same radiating aperture, allowing each antenna to operate independently without interfering with the others through proper design. Due to its advantages such as small aperture size and high integration, it has attracted attention in satellite communication systems.

[0003] The antenna elements used in the broadband common aperture terminal are common aperture elements, and they are small frequency ratio common aperture elements with a frequency ratio of 1.5. Typical application scenarios are millimeter wave satellite communication systems and military radar systems.

[0004] Currently, based on the hollowing-out technique, areas with weak electric fields in the receiving patch antenna are replaced with transmitting antennas to achieve a common-aperture radiating element for both transmitting and receiving. To achieve isolation between the transmitting and receiving radiating elements, shielding holes need to be drilled between the two elements to confine the electric field. The traditional common-aperture terminal antenna element design uses a circular patch antenna without chamfers. By adding U-shaped slots, the current flow path on the antenna surface is changed, generating new resonant points to broaden the antenna bandwidth. Through U-shaped slots with different arm lengths, the current flow paths in two orthogonal directions are different, thereby achieving two orthogonal polarizations with approximately the same amplitude but a 90° phase difference in the orthogonal directions, thus achieving circular polarization.

[0005] The transmitting unit uses a coaxial probe (non-center-fed) for direct feeding, achieving left-hand circular polarization through U-shaped slots of unequal arm lengths (loading U-shaped slots of different arm lengths causes the antenna pattern to deflect, resulting in poor equalization of the transmitting unit's antenna pattern and a certain degree of pattern deflection; furthermore, non-center feeding causes some interference to the subsequent chip arrangement). The receiving unit uses a dual-feed configuration, achieving right-hand circular polarization through a stripline-type phase-shifting power divider network (this method can achieve a wider axial ratio bandwidth than single-feed, but the feeding network introduces losses, reducing the array efficiency after antenna arraying). Furthermore, due to physical size limitations, the existing technology requires increasing the element spacing during arraying to meet physical size requirements; the receiving unit array spacing is 0.53λ. L The spacing between the transmitting elements is 0.56λ. H Increasing the array spacing degrades the scanning performance when using this antenna element array, limiting scanning to within 50°. Summary of the Invention

[0006] This invention provides an antenna element and array for a broadband common-aperture terminal for low-Earth orbit satellite internet. It replaces the weak electric field area of ​​the receiving patch antenna with a transmitting antenna to achieve a common-aperture radiating element for both transmitting and receiving. Shielding holes are drilled between the transmitting and receiving elements. The antenna is center-fed via a coaxial probe and uses a U-shaped slot of equal arm length to achieve a wider operating bandwidth and reduce the size of the transmitting element. Left-hand circular polarization is achieved through chamfering. This method makes the antenna element easier to manufacture, and center feeding also facilitates subsequent wiring. The receiving element uses chamfering to achieve right-hand circular polarization and is fed by an improved L-shaped probe (T-shaped probe) to achieve a wider operating bandwidth. The array spacing between the receiving elements is 0.45λ. L The spacing between the transmitting elements is 0.38λ. H It can achieve a 60° scan.

[0007] This invention is achieved through the following technical solution:

[0008] An antenna unit for a low-orbit satellite internet broadband common-aperture terminal includes a base layer, a middle layer and a top layer that are fixedly connected from bottom to top;

[0009] The top layer has an outer metal cap etched on its upper surface. The top layer also has a transmitter patch and a receiver patch, both of which have been chamfered, attached to its upper surface. The receiver patch is located inside the outer metal cap, and the transmitter patch is located inside the receiver patch. A shielding hole is provided between the receiver patch and the transmitter patch.

[0010] The emitter patch has a U-shaped slit with equal arm length. A first feed coaxial cable is provided perpendicular to the surface of the emitter patch. The first feed coaxial cable is located at the center of the emitter patch, and the top and bottom of the first feed coaxial cable are respectively connected to the emitter patch and the substrate layer.

[0011] The intermediate layer is provided with a T-shaped metal patch, and the vertical part of the T-shaped metal patch is located on the diagonal of the intermediate layer, and the T-shaped metal patch is symmetrical about the diagonal; specifically, the T-shaped metal patch is positioned such that the end of the vertical part of the T-shaped metal patch is 0.04λ away from a vertex of the square containing the intermediate layer. L At the position, λ L It is the wavelength of the lowest frequency point in the receiving band.

[0012] A second power feeding coaxial cable is provided perpendicular to the surface of the receiving patch. The top and bottom of the second power feeding coaxial cable are respectively connected to the T-shaped metal patch and the substrate layer, and the second power feeding coaxial cable is perpendicular to the end of the vertical part of the T-shaped metal patch away from the horizontal part of the T-shaped metal patch.

[0013] As an optimization, the base layer includes a metal base plate and a first dielectric plate from bottom to top, the middle layer is a prepreg (PP), and the top layer includes a second dielectric plate.

[0014] As an optimization, the T-shaped metal patch is attached to the upper surface of the first medium plate and the lower surface of the prepreg PP.

[0015] As an optimization, the first coaxial projection of the power supply is located within the "U" shape formed by the U-shaped gap on the horizontal plane where the transmitting patch is located.

[0016] As an optimization, a plurality of outer ring metal through holes are provided perpendicular to the surface of the second dielectric plate and extending through the second dielectric plate. The projections of the plurality of outer ring metal through holes on the second dielectric plate are all located on the edge of the outer ring metal cap. The outer ring metal through holes extend through the second dielectric plate to the first dielectric plate.

[0017] As an optimization, a plurality of inner ring metal through holes are provided along the edge of the shielding hole and perpendicular to the surface of the second dielectric plate, penetrating the second dielectric plate and extending to the first dielectric plate.

[0018] As an optimization, with the horizontal part of the U-shaped gap as the x-axis and the vertical part as the y-axis, the chamfer of the transmitting patch is set at 45° with the x-axis, and the transmitting patch has two chamfers, which are centrally symmetrical about the first feed axis.

[0019] As an optimization, the horizontal part of the U-shaped gap is taken as the x-axis and the vertical part as the y-axis, and the chamfer of the emitting patch is set along the direction of the y-axis.

[0020] As an optimization, the four corners of the outer metal cap are provided with arcs of 1 / 4 circumference, the convex surface of the arcs facing the center of the top layer, and the radius of the outer metal through hole is the same as the radius of the inner metal through hole.

[0021] The present invention also discloses an array in which the receiving unit, consisting of the receiving patch, the second feeding coaxial cable, and the T-shaped metal patch of the antenna unit applied to the low-orbit satellite internet broadband common aperture terminal, is arranged in a rectangular grid array, and four of the receiving units are rotated 90° for feeding; the transmitting unit, consisting of the transmitting patch and the first feeding coaxial cable, is arranged in a triangular grid array, and four of the transmitting units are rotated 90° for feeding.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] 1. For common-aperture antennas with a frequency ratio of 1.5, this invention solves the bandwidth problem of traditional common-aperture antennas by using a nested transmit / receive structure, a center short-circuit structure (i.e., a ring of grounded metal pillars outside the transmitting unit), and T-shaped probe feeding, thereby expanding the relative bandwidth from the traditional 5% bandwidth to 18%. The simulation results of the traditional small-frequency-ratio common-aperture antenna unit referenced in this invention show a transmit / receive bandwidth of only 5%, while the antenna of this invention can achieve a receive bandwidth of 18% and a transmit bandwidth of 12%, covering the operating frequency band required for low-orbit satellite mobile communication.

[0024] 2. For a common aperture unit with a small frequency ratio of 1.5, the T-shaped metal patch of the receiving unit of the present invention is located in the feeding layer of the receiving unit, while the feeding of the transmitting unit adopts a center direct feeding method that runs from the metal ground all the way to the patch layer. The strong coupling problem between the transmitting and receiving units of the traditional common aperture antenna is solved by the center short-circuit structure and the feeding method of different layers.

[0025] 3. In terms of array configuration, the antenna element size in this invention is smaller than that of traditional common-aperture elements (traditional common-aperture antennas use a receiver element array spacing of 0.53λ). L The spacing between the transmitting elements is 0.56λ. H The present invention uses a receiving element array spacing of 0.45λ. L The spacing between the transmitting elements is 0.38λ. H This allows for smaller array spacing and a larger scanning angle after arraying (the traditional scanning angle is within 50°, while this invention can achieve 60° scanning). Furthermore, the transmitting unit adopts a triangular array configuration, which saves array area compared to the traditional rectangular array configuration.

[0026] 4. In the transmit / receive nested configuration, this invention can achieve wide bandwidth angle scanning (the bandwidth is wider than that of traditional small frequency ratio co-aperture antennas, and the wide angle is 60° compared to the traditional scanning value of 50°). The phased array composed of this antenna has no significant difference in scanning performance compared to the transmit / receive separate phased array. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0028] Figure 1 This is a schematic diagram of the structure of an antenna unit for a low-orbit satellite internet broadband common-aperture terminal as described in this invention;

[0029] Figure 2 for Figure 1 Top view;

[0030] Figure 3 for Figure 1 A bottom view;

[0031] Figure 4 for Figure 1 A bottom view showing the location of the T-shaped metal patch;

[0032] Figure 5 This is an array of 2x2 antenna elements in the embodiment;

[0033] Figure 6 This is a comparison diagram of the feed layers for the transmitting and receiving units.

[0034] The attached diagram shows the markings and corresponding component names:

[0035] 1-Metal base plate, 201-First dielectric plate, 202-Prepreg (PP), 203-Second dielectric plate, 3-Outer metal cap, 401-Outer metallized via, 402-Inner metallized via, 5-Emitter patch, 6-First feed coaxial, 7-Receiver patch, 8-U-shaped slot, 9-Second feed coaxial, 10-T-shaped metal patch. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0037] Example 1

[0038] like Figure 1-6 As shown, an antenna unit for a low-orbit satellite internet broadband common-aperture terminal includes a metal base plate 1, a first dielectric substrate 201, a prepreg PP 202, a second dielectric substrate 203, an outer metal cap 3, an outer metallized via 401, an inner metallized via 402, a transmitting patch 5, a first feed coaxial cable 6, a receiving patch 7, a U-shaped slot 8, a second feed coaxial cable 9, and a T-shaped metal patch 10.

[0039] Specifically, the metal base plate 1 is below the first dielectric plate 201, the prepreg PP 202 connects the first dielectric plate 201 and the second dielectric plate 203, the outer ring metal cap 3 is etched on the upper surface of the second dielectric plate 203, the height of the outer ring metallized via 401 and the inner ring metallized via 402 are both from the second dielectric plate 203 to the first dielectric plate 201 (the metallized via must penetrate the first dielectric plate), the transmitting patch 5 and the receiving patch 7 are both on the upper surface of the second dielectric plate 203, the U-shaped slot 8 is opened on the transmitting patch 5, the first feed coaxial 6 is connected to the center of the transmitting patch 5, the second feed coaxial 9 and the T-shaped metal patch 10 are combined to form a T-shaped probe, the T-shaped metal patch 10 is placed on the upper surface of the first dielectric plate 201 and the lower surface of the prepreg PP 202, and the second feed coaxial 9 is connected to the end of the vertical part of the T-shaped metal patch 10 away from the horizontal part of the T-shaped metal patch 10.

[0040] Both the transmitting patch 5 and the receiving patch 7 have chamfered edges. Specifically, with the horizontal portion of the U-shaped gap 8 as the x-axis and the vertical portion as the y-axis, the chamfer of the transmitting patch 5 is set at 45° to the x-axis, and there are two chamfers on the transmitting patch 5, which are centrally symmetrical about the first feed coaxial 6. By loading the U-shaped gap 8, the transmitting patch 5 can achieve center feeding of the first feed coaxial 6, and the size of the transmitting patch 5 is also reduced. The chamfering at 45° upward and 45° downward on the transmitting patch 5 achieves right-hand circular polarization.

[0041] The receiving patch 6 is coupled and fed through a T-shaped probe composed of a second feeding coaxial cable 9 and a T-shaped metal patch 10. The horizontal portion of the U-shaped gap is taken as the x-axis, and the vertical portion as the y-axis. The angle of the transmitting patch is set along the y-axis direction. Figure 2 As shown, the receiving patch 6 is chamfered on both the left and right sides to achieve left-hand circular polarization. The second feeding coaxial 9 and the T-shaped metal patch 10 are both on the diagonal of the entire second dielectric plate, and the T-shaped metal patch 10 is symmetrical about the diagonal.

[0042] In this invention, λ H λ is the wavelength of the highest frequency point in the transmission frequency band. L λ is the wavelength of the lowest frequency point in the receiving band, and λ is the wavelength of the center frequency point in the transmitting band.

[0043] The receiving unit, composed of a receiving patch, a second coaxial feed, and a T-shaped metal patch, and the transmitting unit, composed of a transmitting patch and a first coaxial feed, have the same thickness and can be processed simultaneously. Compared with a phased array with separate transmit and receive components, this reduces the PCB board area and only requires two pressing steps, thus saving material and process costs.

[0044] A plurality of inner ring metal through-holes 402 are provided along the edge of the shielding hole and perpendicular to the surface of the second dielectric plate, penetrating the second dielectric plate. The inner ring metal through-holes 402 form a circle, confining the excitation field of the transmitting unit 5 within the circle, with a radius of approximately 0.2λ. H This radius refers to the radius of the inner ring of metal vias (forming a ring with a radius of 0.2λ). H The radius of the transmitting unit is 0.2 mm smaller than the radius of the inner metal through hole. This value is mainly for the convenience of engineering implementation. The spacing is 1 / 8λ based on the processing accuracy and the simulation ability to bind the excitation field.

[0045] The outer ring metal through-holes 401, when combined, have rounded corners and are connected by straight lines in the middle. The rounded corners are quarter-circles with radii the same as the central transmitting unit. The convex surfaces of the rounded corners face the center of the top layer and have the same radius as the inner ring metal through-holes 402. The spacing between each outer ring metal through-hole 401 is approximately 1 / 8λ. The outer ring metal through-holes 401 confine the field excited by the receiving unit between the outer ring metal through-holes 401 and the inner ring metal through-holes 402, ensuring the inter-frequency isolation of the antenna unit.

[0046] This invention provides two types of metallic vias, with a spacing of less than λ / 8. The first type is a via at the antenna edge, consisting of a perimeter plus a quarter circle at each of the four corners. This type of via serves as the receiving unit's metallic via, aiming to reduce surface wave interference and gain loss during large-angle scanning. The second type is a ring of vias at the center of the receiving unit. This type of via reduces the area of ​​the receiving patch and, as the boundary of the transmitting unit, provides isolation between the transmitting and receiving units, reducing coupling between them. In this invention, the T-shaped metallic patch of the receiving unit is located on the feed layer, while the transmitting unit's feed uses a center-direct feed method, extending from the metal ground to the patch layer. This center-short-circuit structure and the method of feeding from different layers solve the strong coupling problem between the transmitting and receiving units of traditional common-aperture antennas. Figure 6 As shown.

[0047] Example 2

[0048] The receiving unit, consisting of the receiving patch, the second coaxial feed, and the T-shaped metal patch, of the antenna element used in the low-orbit satellite internet broadband common-aperture terminal described above, is arranged in a rectangular grid array, and four of these receiving units are rotated 90° for feeding. Similarly, the transmitting unit, consisting of the transmitting patch and the first coaxial feed, is arranged in a triangular grid array, and four of these transmitting units are rotated 90° for feeding. This method improves the axial ratio of the array antenna, such as... Figure 5As shown, this is a 2x2 antenna array. The receiving elements are white circles, arranged in a rectangular array of four, with rotating feed. The transmitting elements are black circles, arranged in a triangular array, also with rotating feed in groups of four. To achieve better circular polarization and a more optimal axial ratio, secondary circular polarization (i.e., rotating feed) is required. Therefore, rotating feed is applied to the triangular array, with groups of four (parallelograms in the diagram).

[0049] This invention also employs a cutout technique, replacing the weaker electric field area of ​​the receiving patch antenna with a transmitting antenna to achieve a radiating element with a common aperture for both transmitting and receiving. Shielding holes are drilled between the transmitting and receiving elements, and the antenna is center-fed via a coaxial probe. A U-shaped gap of equal arm length is used to achieve a wider operating bandwidth and reduce the size of the transmitting element. Left-hand circular polarization is achieved through chamfering, which makes the antenna easier to manufacture. At the same time, center feeding also facilitates subsequent wiring. The receiving element uses chamfering to achieve right-hand circular polarization and is fed by an improved L-probe (T-shaped probe) to achieve a wider operating bandwidth. Meanwhile, the array spacing of the receiving elements is 0.45λL, and the array spacing of the transmitting elements is 0.38λH, enabling 60° scanning.

[0050] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An antenna unit for use in a low-orbit satellite internet broadband common-aperture terminal, characterized in that, It includes a base layer, an intermediate layer, and a top layer that are fixedly connected from bottom to top; The top layer has an outer metal cap etched on its upper surface. The top layer also has a transmitter patch and a receiver patch, both of which have been chamfered, attached to its upper surface. The receiver patch is located inside the outer metal cap, and the transmitter patch is located inside the receiver patch. A shielding hole is provided between the receiver patch and the transmitter patch. The emitter patch has a U-shaped slit with equal arm length. A first feed coaxial cable is provided perpendicular to the surface of the emitter patch. The first feed coaxial cable is located at the center of the emitter patch, and the top and bottom of the first feed coaxial cable are respectively connected to the emitter patch and the substrate layer. The intermediate layer is provided with a T-shaped metal patch, and the vertical part of the T-shaped metal patch is arranged on the diagonal of the intermediate layer, and the T-shaped metal patch is symmetrical about the diagonal. A second power feeding coaxial cable is provided perpendicular to the surface of the receiving patch. The top and bottom of the second power feeding coaxial cable are respectively connected to the T-shaped metal patch and the substrate layer, and the second power feeding coaxial cable is perpendicular to the end of the vertical part of the T-shaped metal patch away from the horizontal part of the T-shaped metal patch.

2. The antenna unit for a low-orbit satellite internet broadband common-aperture terminal according to claim 1, characterized in that, The base layer comprises, from bottom to top, a metal base plate and a first dielectric plate, the middle layer is a prepreg (PP), and the top layer comprises a second dielectric plate.

3. An antenna unit for a low-orbit satellite internet broadband common-aperture terminal according to claim 2, characterized in that, The T-shaped metal patch is attached to the upper surface of the first medium plate and the lower surface of the prepreg PP.

4. The antenna unit for a low-orbit satellite internet broadband common-aperture terminal according to claim 1, characterized in that, The first coaxial projection of the feed is located on the horizontal plane where the transmitting patch is located within the "U" shape formed by the U-shaped gap.

5. An antenna unit for a low-orbit satellite internet broadband common-aperture terminal according to claim 2, characterized in that, A plurality of outer ring metal through holes are provided perpendicular to the surface of the second dielectric plate and extending through the second dielectric plate. The projections of the plurality of outer ring metal through holes on the second dielectric plate are all located on the edge of the outer ring metal cap. The outer ring metal through holes extend through the second dielectric plate to the first dielectric plate.

6. An antenna unit for a low-orbit satellite internet broadband common-aperture terminal according to claim 5, characterized in that, A plurality of inner ring metal through holes are provided along the edge of the shielding hole and perpendicular to the surface of the second dielectric plate, penetrating the second dielectric plate to the first dielectric plate.

7. An antenna unit for a low-orbit satellite internet broadband common-aperture terminal according to claim 1, characterized in that, With the horizontal part of the U-shaped gap as the x-axis and the vertical part as the y-axis, the chamfer of the transmitting patch is set at 45° with the x-axis, and the transmitting patch has two chamfers, which are centrally symmetrical about the first feed axis.

8. An antenna unit for a low-orbit satellite internet broadband common-aperture terminal according to claim 1, characterized in that, With the horizontal portion of the U-shaped slit as the x-axis and the vertical portion as the y-axis, the chamfer of the emitting patch is set along the direction of the y-axis.

9. An antenna unit for a low-orbit satellite internet broadband common-aperture terminal according to claim 6, characterized in that, The outer metal cap has four corners with arcs of 1 / 4 circumference, the convex surface of which faces the center of the top layer, and the radius of the outer metal through hole is the same as the radius of the inner metal through hole.

10. An array, characterized in that, The receiving unit, consisting of the receiving patch, the second feeding coaxial cable, and the T-shaped metal patch of the antenna unit applied to the low-orbit satellite internet broadband common aperture terminal as described in any one of claims 1-9, is arranged in a rectangular grid array, and four of the receiving units are rotated 90° for feeding; the transmitting unit, consisting of the transmitting patch and the first feeding coaxial cable, is arranged in a triangular grid array, and four of the transmitting units are rotated 90° for feeding.

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